Generating input binary sequences in an order

Hi,

I have a binary sequence for a 3-bit input which goes like 0-0,0-1,...0-7 (say for a single circuit). I want to iterate this for 3 circuits...which would effectively lead to the same input transitions being repeated over (2^3)^3 times (but in different orders like 0-5,0-1,0-3, ..etc and so on..) How can I do this in MATLAB?

I tried using repmat...but it was not much of a help...Thanks!

[Jan]

I do not understand how a "3-bit input" is represented as " 0-0,0-1,...0-7" exactly.

This is not twitter: No # before the tags. Thanks.

[Stephen23]

@Kash022: this is not twitter. Tags do not need # in them. Today I removed them for you.

[Kash022]

@Jan: a 3-bit input is represented as 000,001,....so the transition would be like

0001000100010001  - input 2
0000010100000101  - input 1
0000000001010101  - input 0

Do you now see the sequence? take each column of [input2 input1 input0] and you will see the sequence 0-0,0-1,0-2,0-3,0-4,0-5,0-6 and 0-7.

[Jan]

@Stephen: I said this already. But I will remove the old hashed tags for you. Or for Kash022. Who knows.

[Jan]

@Kash022: What exactly is 000? Do you mean the char vector '000'? I do not "see the sequence". What is "each column of [input2 input1 input0]"? Is it each character? Does "0-0" mean a [1 x 2] vector? If so, please do not invent a new notation using the minus operator. Standard Matlab syntax is known in the forum: [0,0]

I still do not know, what the inputs are (in Matlab syntax) and what you want to achieve.

Answer 1

[Guillaume]

Like others, I really don't understand the syntax 0-0, 0-7. I get that you've got 8 different possibilities (0 to 7) for choosing two bits at a time, but I've no idea what the 0- represent, nor how you encode that in matlab.

Anyway, there are two easy way to generate all permutations of choosing n elements at a time of a set of size s:

• Using dec2base, this is limited to sets of size 10 at most:

n = 3;
s = 8;
permutations = dec2base(0:s^n-1, s) - '0'

• Using ndgrid, this is less limited, but more lines of code:

n = 3;
s = 8;
permutations = cell(1, n);
[permutations{:}] = ndgrid(0:s-1);
permutations = reshape(cat(n+1, permutations{:}), [], n)

From there, you can change the permutation matrix to whatever you want, e.g. if you wanted to write the 0-7 as char arrays '0-0' to '0-7', then:

fullset = compose('0-%d', 0:7);